<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Size</title>
    <style type="text/css">
        div {
            width: 800px;
            height: 500px;
            background: url("bg1.jpg") no-repeat;
            background-size: contain;
            background-size: cover;
            background-size: 800px 500px;
            background-size: 800px;
            background-size: 50% 50%;
            background-size: 50%;
            background-size: 100% 100%;
            background-size: 100%;
        }
    </style>
</head>
<body>
<div></div>
</body>
</html>